Noise-induced hearing loss is highly prevalent in the US and Canada, and noise is increasingly being linked to other non-auditory health effects such as cardiovascular disease, sleep disturbance, and stress. However, our knowledge of noise exposures associated with many US and Canadian occupations is lacking. The proposed study would develop from existing resources a US/Canadian Job Exposure Matrix (JEM) for noise which would allow for estimation of workplace noise exposures on a national scale. This JEM would give researchers a vital tool which could dramatically improve the accuracy and efficiency of noise exposure assessments. We will leverage existing noise measurement data obtained from a wide variety of regulatory and research agencies, individual researchers, and industry sources to efficiently create the JEM, which would contain estimates of mean noise exposure levels coded to standardized industry and occupation classifications, as well as estimates of the prevalence of overexposure to noise. We will supplement collected noise measurements with data from O*NET, a publicly available database that includes worker-reported noise levels for different occupations. We will also use O*NET data and expert assessment to validate the JEM. Once the JEM is finalized, we will develop a web-based tool to allow epidemiologists, occupational hygienists, occupational health practitioners and other relevant stakeholders to access the noise exposure estimates. Dissemination of this free tool would inform campaigns for targeted exposure reduction, help identify and prioritize research needs, and help manage workers compensation claims. Development of the JEM directly addresses three cross-sector programs within NIOSH's National Occupational Research Agenda: hearing loss prevention, exposure assessment, and communications and information dissemination. The study also addresses several goals of Healthy People 2020. The primary study outputs will be a national noise JEM, complementary web-based JEM tool, and several peer-reviewed manuscripts. Intermediate outcomes may include additional studies of health effects associated with noise made possible by the availability of the JEM, as well as targeted interventions directed by the JEM results. The end outcome of the project would be a long- term reduction in NIHL and non-auditory health effects of noise resulting from occupational health interventions. The study focuses on the translation and dissemination of existing knowledge to relevant end users (researchers and occupational health practitioners) for use and implementation in both workplace and research settings. This focus aligns very well with NIOSH's Research to Practice (r2p) initiative.